NEX ROBOTICS Fire Bird V ATMEGA2560 Software Manual page 69

NEX Robotics
4.2.1 Calculation of position encoder resolution:
Case 1: Robot is moving forward or backward (encoder resolution is in mm)
Wheel diameter: 5.1cm
Wheel circumference: 5.1cm * 3.14 = 16.014cm = 160.14mm
Number slots on the encoder disc: 30
Position encoder resolution: 163.2 mm / 30 = 5.44mm / pulse.
Case 2: Robot is turning with one wheel rotating clockwise while other wheel is rotating
anti clockwise. Center of rotation is in the center of line passing through wheel axel and
both wheels are rotating in opposite direction (encoder resolution is in degrees)
Distance between Wheels = 15cm
Radius of Circle formed in 360
Distance Covered by Robot in 360
Number of wheel rotations of in 360
0
Total pulses in 360
= Number of slots on the encoder disc / Number of wheel rotations of in 360
= 30 x 2.941
= 88.23 (approximately 88)
Position Encoder Resolution in Degrees = 360 / 88
Case 3: Robot is turning with one wheel stationary while other wheel is rotating clockwise
or anti clockwise. Center of rotation is center of the stationary wheel (encoder resolution is
in degrees)
In this case only one wheel is rotating and other wheel is stationary so robot will complete its
0
360 rotation with stationary wheel as its center.
Radius of Circle formed in 360
Distance Covered by Robot in 360
Number of wheel rotations of in 360
www.nex-robotics.com
0
rotation of Robot = Distance between Wheels / 2
0
Rotation = Circumference of Circle traced
0
rotation of robot
= Circumference of Traced Circle / Circumference of Wheel
= 471 / 160.14
= 2.941
Rotation of Robot
= 4.090 degrees per count
0
rotation of Robot = Distance between Wheels
0
Rotation = Circumference of Circle traced
0
rotation of robot
= Circumference of Traced Circle / Circumference of Wheel
= 942 / 160.14
= 5.882
Fire Bird V Software Manual
= 7.5 cm
= 2 x 7.5 x 3.14
= 47.1 cm or 471mm
= 15 cm
= 2 x 15 x 3.14
= 94.20 cm or 942 mm
0
rotation of robot
69